In the radio communication system, a mobile station may move within a cell or between cells of a radio base station, causing change in the communication quality according to the move of the mobile station and the passing of time. It has been known that, in connection with change in the communication quality, for example, a rapid deterioration in the communication quality causes technical problems such as a decrease in the data transmission efficiency and sometimes disconnection of transmission.
As a solution for such problems, in order to maintain preferable communication, a method to predict change in the communication quality based on an estimated moving route of the mobile station and to realize efficient communication is studied. Related techniques are disclosed in Japanese Laid-open Patent Publication No. 2008-236381 and Japanese Laid-open Patent Publication No. 2008-199381.
However, the conventional techniques have following problems.    (1) Even if an area in which efficient communication can be performed is selected from an estimated moving route, the area may be far away from the current position of the mobile station. In such a case, since the use would be kept waiting for a long time before the start of data transmission/reception, it is not convenient enough.    (2) Since change in the communication quality within a cell cannot be handled, efficient communication may not necessarily be realized.    (3) In the state where the communication quality is bad, since the data transmission rate is set low and the transmission interval is set long, completion of data transmission requires a long time. In this case, the radio resource of the base station is occupied for a long period of time, thus the radio resource is not used efficiently and it is inconvenient for the user.